sql: regression test for MVCC timestamp in materialized views

Before abeaf01 this test would have
failed, so this test will help make sure we don't regress.

Release note: None

pkg/sql/logictest/testdata/logic_test/materialized_view

@@ -29,6 +29,9 @@ SELECT * FROM v
 3 4
 5 6
 
+let $orig_crdb_timestamp
+SELECT max(crdb_internal_mvcc_timestamp) FROM v
+
 # Now refresh the view.
 statement ok
 REFRESH MATERIALIZED VIEW v
@@ -42,6 +45,12 @@ SELECT * FROM v
 5 6
 7 8
 
+# Verify that crdb_internal_mvcc_timestamp is updated for all rows.
+query I
+SELECT count(*) FROM v WHERE crdb_internal_mvcc_timestamp > $orig_crdb_timestamp
+----
+4
+
 # Now add an index to the view, and use it.
 statement ok
 CREATE INDEX i ON v (y)